Such acoustic signal generators --constituted by one or more horns and a generally cylindrical electric compressor serving as a source of air under pressure--are conventionally installed on the body of the vehicle by providing the electric compressor during manufacture with a mounting strap or using a collar strap to be applied to the compressor at the installation site; by means of two screws, the strap--and thus the compressor--is fixed to the vehicle body which is suitably perforated. The horns, on the other hand, have a muff provided with a stud, or threaded for receiving a screw, or else they are provided--by soldering--with mounting straps; in any case, however, the horn is directly secured to the vehicle body, thus requiring further apertures in that body.
These solutions present several inconveniences: in particular, they require specific mounting means--such as the straps, the stud, the threading etc.--which must be specifically produced, thus increasing the production costs.